With the current abuse of bugzilla flags, one really needs the ability to
properly query them. These changes allow multiple '--flag' options and
gives the user the ability to use '&,|' options with the flags.

For example, now you can do
--flag 'rhel-5.4.0? | rhel-5.4.0+' --flag 'blocker? | blocker+'

Now the ability to separate the flag commands like above is important for
the negation command later, where negation only works on the flag group it
is apart of.